Research Summary:
Research in our group can be broadly characterised as investigations of the structure property-relationship in complex polymer materials including semi-crystalline polymers, multiphase copolymers, nano-structured polymers and nano-filled polymer composite. We are interested in the synthesis of these materials as well as in the development of novel analytical approaches and techniques to characterise these materials.

Research Description:
Hybrid Materials:
Polymer hybrid materials based on polydimethylsiloxane (PDMS) have many potential applications. These hybrid polymer materials combine the properties of the organic and inorganic segments to produce new materials with interesting properties. The incompatibility of the various components in the polymer lead to nano-phase segregated systems and interesting morphologies in the solid state. In this project we are interested in the synthesis of these hybrid materials using controlled polymerisation techniques as well as the development of analytical techniques to characterise these materials. Techniques that are being developed including 2-dimensional liquid chromatography techniques and the “offline coupling” of chromatographic separations (LC-CC, Gradient elution chromatography and SEC) to techniques for the study of polymer morphology (eg: TEM and AFM). We are also interested in exploiting the surface segregation phenomena in these materials by for example producing nano-fibres of the materials using the electrospinning technique. This process leads to “superhydrophobic” surfaces.



Polyolefins:
Polyolefins are by far the most important of the commercially produced polymers. These polymers are of interest since they are chemically the simplest polymers, but they can be produced with vastly different physical properties by simply changing the architecture (structure) of the polymer chains. By manipulation of the chain structure it is possible to produce materials that are very soft and rubbery as well as materials that are hard and brittle. The processes used to make these polymers inevitably leads to materials with polymer chains that have a heterogeneous distribution in chain branching as well as chain length. In order to fully understand the relationship between the chain structure and the properties it is necessary to use multiple fractionation techniques. In this project we make use of hyphenated crystallization fractionation techniques (2-dimensional crystallization analysis) including temperature rising elution fractionation (TREF) and CRYSTAF in order to get a better understanding of the relationship between the polymer structure, the morphology and the physical properties. Other techniques that we are using include positron annihilation lifetime spectroscopy to understand the relationship between the free volume properties and the chain structure in these semi-crystalline materials. We are also developing multiple hyphenated fractionation techniques including TREF-SEC-LC transform-FTIR to study the mechanism of degradation in impact polypropylene polymers.